Well, the equations that predict black holes also predict white holes, and the big bang is functionally equivalent to a white hole. And we have found black holes. So…seems like the most plausible explanation for the big bang is…it was a white hole. Still can’t extrapolate backwards for the same reasons, but there are at least implicit causes of white holes suggesting there was spacetime before the big bang.
Well, the equations that predict black holes also predict white holes, and the big bang is functionally equivalent to a white hole. And we have found black holes. So…seems like the most plausible explanation for the big bang is…it was a white hole. Still can’t extrapolate backwards for the same reasons, but there are at least implicit causes of white holes suggesting there was spacetime before the big bang.